If you read the end of the OP it's all explained
It will wipe all apps and their data, but NOT photos, videos, music or downloads. But you should have the apps and their data backed up anyway. Wiping data is NOT the same as formatting it.
Well, you don't have to format it, but you probably should flash CSC instead of HOME_CSC when going from A11 to A12. But then again, just try it with HOME_CSC, you can still do another flash with CSC if necessary.
So, coming from an already rooted tablet, I should be able to skip step 7?
Hope I can just reboot after step 6 and boot back into the system, upgraded to A12!
Just try flashing the ROM update with Odin without patching anything along the way and see if it works. What do you have to lose when the alternative is a factory reset anyway? :-D
I've got very little experience with Samsung and odin, which file is the rom update?
Just perform steps 3-6, this will also include patching the AP part of the ROM via Magisk, which gives you root. I don't think step 7 (Factory Reset) is necessary but I haven't tried it myself since I am already on the newest version.
Confirmed that steps 3-6 worked.
follow all the tutorial from first page, at step 6 you need to do everything, BUT when you are selecting files within odin, don't put the magisk patched.tar, then (important thing i needed to do with the vb meta error like you):
Thank You so much I had the same error, your solution fixed it.
That's completely alright. I can understand.Hey man, I wanna take the time to apologize for that PM, that was uncalled for from my end. Ive been working with jailbreaking and rooting phones and tablets for 10+ years (2005-2015 mainly). I usually know what the hell Im doing XD
I did read your guide thoroughly, but I misunderstood the part about soft reboot and hard reboot. Im new to Samsung with OS10 and the latest Knox functions. I think where it went wrong for me was after the Factory Reset inside the Recovery menu. While rebooting, it got stuck somewhere. I waited for a long while, but I concluded with a hard restart. (volume down + power)
The mistake, as you wrote, probably happened during this hard restart, where Knox got tripped and it got stuck with "Only official released binaries are allowed to be flashed (vbmeta)" error.
The problem tho, is after this state (knox tripped, and warrantystatus 0x01) it seemed impossible to reflash with Odin. As no matter what I tried (Stock rom, magisk repeat) it still wouldnt let me flash the Patched AP again. Download mode stopped Odin with the same red line "Custom binary VBmeta". I might be mistaken, but it seems that after Knox is tripped, if Magisk doesnt get to do its thing, it winds up locked without possibility of reflashing patched AP.
Anyways, the end of the story for my Tab A7 was that I flashed stock rom, locked the bootloader and asked for a refund from the store. They didnt check Knox and I exchanged it for a Lenovo MT10+ instead. Better CPU and ram, and cheaper than the Samsung. So a happy ending anyways
A couple of things tho:
1) Odin 3.14.4 doesnt seem to exist, Ive roamed the forums and google for this version, and most sites have a bogus download where the CRC is all wrong. The correct latest version is 3.14.1. You might wanna change this in your guide, so people dont get lead down the wrong path.
2) I would highly recommend expressing the importance of not actually hard rebooting your device before Magisk does its finishing touches. Maybe big letters in red and "Warning warning"? Especially seeing as a couple of other members here did the same mistake.
Again, sorry for my noob-rage. I got kinda carried away. Thanks for all the effort youve put into this guide, @DJBhardwaj. Ill read your guide better next time
Greetings from Norway
Take care and enjoy your new Lenovo tab. Hope you find some exciting things to do with it as well. 
